$b(n) = 1 \left(-2\right)^{n - 1}$ What is the $4^\text{th}$ term in the sequence?
Answer: This is an explicit formula. All we have to do is plug $n=4$ in the formula to find the $4^\text{th}$ term. $\begin{aligned} b({4}) &=1(-2)^{{4} - 1} \\\\ &= -8 \end{aligned}$ The $4^\text{th}$ term is $-8$.